Today, we remember the lives of those lost and the heroes who paid the ultimate sacrifice to protect our freedom. Over 1,000 family members, survivors, rescuers and officials were gathered as they paid respect to all who lost their lives on 9/11/01. Family members of those who were killed began reading out the names of nearly 3,000 people.

(Carmen Taylor / Associated Press)

United Airlines Flight 175 flies into the South Tower at 9:03 a.m. on Tuesday, Sept. 11, 2001.

(Det. Greg Semendinger / NYPD)

A damaged tower collapses.

(Thomas E. Franklin / Associated Press)

Firefighters raise a flag late in the afternoon of Sept. 11, 2001, in the wreckage of the World Trade Center towers.

(Gulnara Samoilova / Associated Press)

People covered in dust walk over debris near the World Trade Center in New York.

(RICHARD DREW / Associated Press)

A person jumps from the burning North Tower of the World Trade Center as another clings to the outside, left center.

(Daniel Hulshizer / Associated Press)

Thick smoke billows behind the Statue of Liberty from where the towers once stood.

(Alex Fuchs / Associated Press)

The remains of the World Trade Center.

(Suzanne Plunkett / Associated Press)

People flee as a World Trade Center tower collapses behind them.

(Doug Kanter / AFP/Getty Images)

A man stands in the rubble of the World Trade Center and calls out, asking if anyone needs help,

(Hubert Michael Boesl / AFP/Getty Images)

Smoke billows from the top floors of the World Trade Center towers.

(Seth Wenig / Associated Press)

Flowers cover the names of the victims of the 9/11 terrorist attacks before a ceremony at Ground Zero in New York on Monday.